AllowCookies is a published Boolean property in TIdHTTP, and indicates if the HTTP client allows use of persistent state information using TIdCookie instances handled by CookieManager. AllowCookies is used when an HTTP client retrieves headers for an HTTP Response, and processes Response headers and cookie values. 

When AllowCookies is True, the HTTP client will ensure that CookieManager is instantiated prior to adding any TIdCookieRFC2109 or TIdCookieRFC2965 cookie instances detected in Response headers. 

The default value for AllowCookies is True, as assigned in the Create constructor.

TIdCustomHTTP.CookieManager 

TIdCookieRFC2109 

TIdCookieRFC2965